Ofcom has revealed EE is the most reliable mobile network, achieving the fastest mobile data speeds in Cardiff, Edinburgh, Liverpool and London.
The regulator tested EE, O2, Vodafone and Three's mobile networks in December 2015 to see which offered up the best performance over both 3G and 4G in the four UK cities and presented its results in the Smartphone Cities report.
The report revealed that web pages on EE's network successfully loaded 98 per cent of the time, taking around five seconds to load, while download speeds were revealed to be an average 20Mbps.
Three came second in the tests, with pages loading 95 per cent of the time and taking six seconds to load - the same as both Vodafone and O2. However, its network boasted average speeds of 15Mbps - much better than Vodafone's 12Mbps and O2's 10Mbps.
London suffered from the slowest web browsing speeds of all cities across all four networks, while Cardiff's were most impressive, especially for EE, where Ofcom was able to take advantage of 23Mbps. The only city where EE didn't come top of the charts was in Norwich, where Three performed best.
However, at the time of the data collection, Ofcom admits that some of the networks may have been undergoing maintenance in some places and therefore, additional metrics should be used when a customer is choosing which network to use.
"The range of metrics featured in the report, and the analysis provided, give consumers an insight into the performance of their mobile network according to how and when they use their smartphone," Ofcom said.
"Network performance is only one of the factors that a consumer is likely to take into account when choosing a mobile phone service. This report is part of a wider programme of work by Ofcom into mobile quality of service, which includes our interactive coverage maps."
Ofcom's Mobile Coverage and Broadband Coverage Checker allows customers to check the coverage and speeds of web browsing and downloads where they live, helping them make an informed choice about which network to sign up to.
